The present invention relates to an air-cooled tube condenser which includes a plurality of elongated heat exchanger tubes arranged in a row and each being covered with transverse fins.
Heat exchanger tubes employed in the tube condensers of the type under discussion have, as compared to presently utilized elliptical, finned tubes, a doubled or three-time larger ratio between the greatest length of the tube and its greatest width; to condense the same amounts of steam, such tubes being arranged in three or more rows positioned in the direction of cooling air flow one after another. The advantage of such tubes resides in that a pressure compensation can be obtained at each place of the tube between all the regions of the tube cross-section. Thereby the condensation of vapor in the front tube portions, facing the flow of cooling air ends exactly at the same time at which its ends in the rear end portion of the tube, as viewed in the direction of cooling air flow. The danger of the occurrence of dead zones is thus evidently prevented or totally eliminated. The required length-width ratios lead to greater inside width of the tubes. Flow pressure losses in the heat exchanger tubes arranged one after another in the direction of cooling air flow and having the same cross-section for condensing the same amounts of vapor have been reduced to fractions as compared to losses in tubes of greater hydraulic diameters.
Despite the fact that heat-exchanger tubes are rather long they have good cross-section stability and can be manufactured with required precision without the danger of being distorted or deformed. Stability of the tube cross-section is so high that further hot dip galvanization or the like heat treatment would present no problem. Heat exchanger tubes which are very long, for example of 10 m, can be finned by means of conventional finning machines.
Although heat exchanger tubes having length-width ratio of about 8:1 and more have proven to be reliable practice has shown that heat transfer coefficients of such tubes can be improved.